As a recording technique using physics of a chalcogenide material, a phase-change memory and a phase-change optical disc are cited. As a phase-change material used for the phase-change memory and the phase-change optical disc, a chalcogenide material containing Te (tellurium) is known.
U.S. Pat. No. 5,254,382 (patent document 1) has disclosed an optical disc medium using a chalcogenide material expressed as {(GeyTe1-y)a(SbzTe1-z)1-a}1-b(In1-xTex)b (Here, 0.4≦y≦0.6, 0.3≦z≦0.6, 0.4≦z≦0.6, 0.1≦b≦0.3) as a recording layer. In this case, for the purpose of improving the stability of an amorphous state while maintaining a characteristic of being able to crystallize rapidly and improving long-term data storage stability, In is added to Ge—Sb—Te.
On the other hand, in U.S. Pat. No. 5,883,827 (patent document 2), a non-volatile memory using a chalcogenide material film has been described in detail. This non-volatile memory is a phase-change memory in which stored information is written by the change in atomic arrangement of a phase-change material film in accordance with Joule heat and cooling rate caused by a current flowing in the phase-change material film itself. For example, since a phase-change material film is once molten by applying heat of higher than 600° C. in Joule heat when forming a noncrystalline (amorphous) state, the operation current tends to be large, and a resistance value changes by two to three orders of magnitude in accordance with the crystalline state.
As for the electrical phase-change memory, studies for that using Ge2Sb2Te5 have been promoted mainly. For example, Japanese Patent Application Laid-Open Publication No. 2002-109797 (patent document 3) has disclosed a recording element using GeSbTe. Also, Japanese Patent Application Laid-Open Publication No. 2003-100991 (patent document 4) has disclosed a technique related to a memory using a chalcogenide material. Moreover, a non-patent document 1 has revealed that a phase-change memory using a phase-change film made of Ge2Sb2Te5 is rewritable 1012 times. Further, a non-patent document 2 has disclosed a technique related to a phase-change memory using a crystal-growth material.
Patent Document 1: U.S. Pat. No. 5,254,382
Patent Document 2: U.S. Pat. No. 5,883,827
Patent Document 3: Japanese Patent Application Laid-Open Publication No. 2002-109797
Patent Document 4: Japanese Patent Application Laid-Open Publication No. 2003-100991
Non-Patent Document 1: IEEE International Electron Devices meeting, TECHNICAL DIGEST, 2001, pp. 803-806
Non-Patent Document 2: Nature Materials, Vol. 4, 2005, pp. 347-351